create.js•10.5 kB
import { List } from '../utils/List.js';
import { SyntaxError } from './SyntaxError.js';
import {
tokenize,
OffsetToLocation,
TokenStream,
tokenNames,
consumeNumber,
findWhiteSpaceStart,
cmpChar,
cmpStr,
WhiteSpace,
Comment,
Ident,
Function as FunctionToken,
Url,
Hash,
Percentage,
Number as NumberToken
} from '../tokenizer/index.js';
import { readSequence } from './sequence.js';
const NOOP = () => {};
const EXCLAMATIONMARK = 0x0021; // U+0021 EXCLAMATION MARK (!)
const NUMBERSIGN = 0x0023; // U+0023 NUMBER SIGN (#)
const SEMICOLON = 0x003B; // U+003B SEMICOLON (;)
const LEFTCURLYBRACKET = 0x007B; // U+007B LEFT CURLY BRACKET ({)
const NULL = 0;
function createParseContext(name) {
return function() {
return this[name]();
};
}
function fetchParseValues(dict) {
const result = Object.create(null);
for (const name in dict) {
const item = dict[name];
const fn = item.parse || item;
if (fn) {
result[name] = fn;
}
}
return result;
}
function processConfig(config) {
const parseConfig = {
context: Object.create(null),
scope: Object.assign(Object.create(null), config.scope),
atrule: fetchParseValues(config.atrule),
pseudo: fetchParseValues(config.pseudo),
node: fetchParseValues(config.node)
};
for (const name in config.parseContext) {
switch (typeof config.parseContext[name]) {
case 'function':
parseConfig.context[name] = config.parseContext[name];
break;
case 'string':
parseConfig.context[name] = createParseContext(config.parseContext[name]);
break;
}
}
return {
config: parseConfig,
...parseConfig,
...parseConfig.node
};
}
export function createParser(config) {
let source = '';
let filename = '<unknown>';
let needPositions = false;
let onParseError = NOOP;
let onParseErrorThrow = false;
const locationMap = new OffsetToLocation();
const parser = Object.assign(new TokenStream(), processConfig(config || {}), {
parseAtrulePrelude: true,
parseRulePrelude: true,
parseValue: true,
parseCustomProperty: false,
readSequence,
consumeUntilBalanceEnd: () => 0,
consumeUntilLeftCurlyBracket(code) {
return code === LEFTCURLYBRACKET ? 1 : 0;
},
consumeUntilLeftCurlyBracketOrSemicolon(code) {
return code === LEFTCURLYBRACKET || code === SEMICOLON ? 1 : 0;
},
consumeUntilExclamationMarkOrSemicolon(code) {
return code === EXCLAMATIONMARK || code === SEMICOLON ? 1 : 0;
},
consumeUntilSemicolonIncluded(code) {
return code === SEMICOLON ? 2 : 0;
},
createList() {
return new List();
},
createSingleNodeList(node) {
return new List().appendData(node);
},
getFirstListNode(list) {
return list && list.first;
},
getLastListNode(list) {
return list && list.last;
},
parseWithFallback(consumer, fallback) {
const startToken = this.tokenIndex;
try {
return consumer.call(this);
} catch (e) {
if (onParseErrorThrow) {
throw e;
}
const fallbackNode = fallback.call(this, startToken);
onParseErrorThrow = true;
onParseError(e, fallbackNode);
onParseErrorThrow = false;
return fallbackNode;
}
},
lookupNonWSType(offset) {
let type;
do {
type = this.lookupType(offset++);
if (type !== WhiteSpace) {
return type;
}
} while (type !== NULL);
return NULL;
},
charCodeAt(offset) {
return offset >= 0 && offset < source.length ? source.charCodeAt(offset) : 0;
},
substring(offsetStart, offsetEnd) {
return source.substring(offsetStart, offsetEnd);
},
substrToCursor(start) {
return this.source.substring(start, this.tokenStart);
},
cmpChar(offset, charCode) {
return cmpChar(source, offset, charCode);
},
cmpStr(offsetStart, offsetEnd, str) {
return cmpStr(source, offsetStart, offsetEnd, str);
},
consume(tokenType) {
const start = this.tokenStart;
this.eat(tokenType);
return this.substrToCursor(start);
},
consumeFunctionName() {
const name = source.substring(this.tokenStart, this.tokenEnd - 1);
this.eat(FunctionToken);
return name;
},
consumeNumber(type) {
const number = source.substring(this.tokenStart, consumeNumber(source, this.tokenStart));
this.eat(type);
return number;
},
eat(tokenType) {
if (this.tokenType !== tokenType) {
const tokenName = tokenNames[tokenType].slice(0, -6).replace(/-/g, ' ').replace(/^./, m => m.toUpperCase());
let message = `${/[[\](){}]/.test(tokenName) ? `"${tokenName}"` : tokenName} is expected`;
let offset = this.tokenStart;
// tweak message and offset
switch (tokenType) {
case Ident:
// when identifier is expected but there is a function or url
if (this.tokenType === FunctionToken || this.tokenType === Url) {
offset = this.tokenEnd - 1;
message = 'Identifier is expected but function found';
} else {
message = 'Identifier is expected';
}
break;
case Hash:
if (this.isDelim(NUMBERSIGN)) {
this.next();
offset++;
message = 'Name is expected';
}
break;
case Percentage:
if (this.tokenType === NumberToken) {
offset = this.tokenEnd;
message = 'Percent sign is expected';
}
break;
}
this.error(message, offset);
}
this.next();
},
eatIdent(name) {
if (this.tokenType !== Ident || this.lookupValue(0, name) === false) {
this.error(`Identifier "${name}" is expected`);
}
this.next();
},
eatDelim(code) {
if (!this.isDelim(code)) {
this.error(`Delim "${String.fromCharCode(code)}" is expected`);
}
this.next();
},
getLocation(start, end) {
if (needPositions) {
return locationMap.getLocationRange(
start,
end,
filename
);
}
return null;
},
getLocationFromList(list) {
if (needPositions) {
const head = this.getFirstListNode(list);
const tail = this.getLastListNode(list);
return locationMap.getLocationRange(
head !== null ? head.loc.start.offset - locationMap.startOffset : this.tokenStart,
tail !== null ? tail.loc.end.offset - locationMap.startOffset : this.tokenStart,
filename
);
}
return null;
},
error(message, offset) {
const location = typeof offset !== 'undefined' && offset < source.length
? locationMap.getLocation(offset)
: this.eof
? locationMap.getLocation(findWhiteSpaceStart(source, source.length - 1))
: locationMap.getLocation(this.tokenStart);
throw new SyntaxError(
message || 'Unexpected input',
source,
location.offset,
location.line,
location.column
);
}
});
const parse = function(source_, options) {
source = source_;
options = options || {};
parser.setSource(source, tokenize);
locationMap.setSource(
source,
options.offset,
options.line,
options.column
);
filename = options.filename || '<unknown>';
needPositions = Boolean(options.positions);
onParseError = typeof options.onParseError === 'function' ? options.onParseError : NOOP;
onParseErrorThrow = false;
parser.parseAtrulePrelude = 'parseAtrulePrelude' in options ? Boolean(options.parseAtrulePrelude) : true;
parser.parseRulePrelude = 'parseRulePrelude' in options ? Boolean(options.parseRulePrelude) : true;
parser.parseValue = 'parseValue' in options ? Boolean(options.parseValue) : true;
parser.parseCustomProperty = 'parseCustomProperty' in options ? Boolean(options.parseCustomProperty) : false;
const { context = 'default', onComment } = options;
if (context in parser.context === false) {
throw new Error('Unknown context `' + context + '`');
}
if (typeof onComment === 'function') {
parser.forEachToken((type, start, end) => {
if (type === Comment) {
const loc = parser.getLocation(start, end);
const value = cmpStr(source, end - 2, end, '*/')
? source.slice(start + 2, end - 2)
: source.slice(start + 2, end);
onComment(value, loc);
}
});
}
const ast = parser.context[context].call(parser, options);
if (!parser.eof) {
parser.error();
}
return ast;
};
return Object.assign(parse, {
SyntaxError,
config: parser.config
});
};